Lulu Zhang, Ismael García-Bernete, Chris Packham, Fergus R. Donnan, Dimitra Rigopoulou, Erin K. S. Hicks, Ric I. Davies, Taro T. Shimizu, Almudena Alonso-Herrero, Cristina Ramos Almeida, Miguel Pereira-Santaella, Claudio Ricci, Andrew J. Bunker, Mason T. Leist, David J. Rosario, Santiago García-Burillo, Laura Hermosa Muñoz, Francoise Combes, Masatoshi Imanishi, Alvaro Labiano, Donaji Esparza-Arredondo, Enrica Bellocchi, Anelise Audibert, Lindsay Fuller, Omaira González-Martín, Sebastian Hönig, Takuma Izumi, Nancy A. Levenson, Enrique López-Rodríguez, Daniel Rouan, Marko Stalevski, Martin J. Ward
We analyze JWST MIRI/MRS IFU observations of three Seyferts and showcase the intriguing polycyclic aromatic hydrocarbon (PAH) emission characteristics in regions of $sim 500,rm pc$ scales over or around their active galactic nuclei (AGN). Combining the model predictions and the measurements of PAH features and other infrared emission lines, we find that the central regions containing a high fraction of neutral PAHs with small sizes, e.g., those in ESO137-G034, are in highly heated environments, due to collisional shock heating, with hard and moderately intense radiation fields. Such environments are proposed to be associated with inhibited growth or preferential erosion of PAHs, decreasing the average PAH size and the overall abundance of PAHs. We additionally find that the central regions containing a high fraction of ionized PAHs with large sizes, e.g., those in MCG-05-23-016, are likely experiencing severe photo-ionization because of the radiative effects from the radiative shock precursor besides the AGN. The severe photo-ionization can contribute to the ionization of all PAHs and further destruction of small PAHs. Overall, different Seyferts, even different regions in the same galaxy, e.g., those in NGC,3081, can contain PAH populations of different properties. Specifically, Seyferts that exhibit similar PAH characteristics to ESO137-G034 and MCG-05-23-016 also tend to have similar emission line properties to them, suggesting that the explanations for PAH characteristics of ESO137-G034 and MCG-05-23-016 may also apply generally. These results have promising application in the era of JWST, especially in diagnosing different (i.e., radiative, and kinetic) AGN feedback modes.
{"title":"The Galaxy Activity, Torus, and Outflow Survey (GATOS). (VI): Polycyclic Aromatic Hydrocarbon Emission in the Central Regions of Three Seyferts","authors":"Lulu Zhang, Ismael García-Bernete, Chris Packham, Fergus R. Donnan, Dimitra Rigopoulou, Erin K. S. Hicks, Ric I. Davies, Taro T. Shimizu, Almudena Alonso-Herrero, Cristina Ramos Almeida, Miguel Pereira-Santaella, Claudio Ricci, Andrew J. Bunker, Mason T. Leist, David J. Rosario, Santiago García-Burillo, Laura Hermosa Muñoz, Francoise Combes, Masatoshi Imanishi, Alvaro Labiano, Donaji Esparza-Arredondo, Enrica Bellocchi, Anelise Audibert, Lindsay Fuller, Omaira González-Martín, Sebastian Hönig, Takuma Izumi, Nancy A. Levenson, Enrique López-Rodríguez, Daniel Rouan, Marko Stalevski, Martin J. Ward","doi":"arxiv-2409.09772","DOIUrl":"https://doi.org/arxiv-2409.09772","url":null,"abstract":"We analyze JWST MIRI/MRS IFU observations of three Seyferts and showcase the\u0000intriguing polycyclic aromatic hydrocarbon (PAH) emission characteristics in\u0000regions of $sim 500,rm pc$ scales over or around their active galactic\u0000nuclei (AGN). Combining the model predictions and the measurements of PAH\u0000features and other infrared emission lines, we find that the central regions\u0000containing a high fraction of neutral PAHs with small sizes, e.g., those in\u0000ESO137-G034, are in highly heated environments, due to collisional shock\u0000heating, with hard and moderately intense radiation fields. Such environments\u0000are proposed to be associated with inhibited growth or preferential erosion of\u0000PAHs, decreasing the average PAH size and the overall abundance of PAHs. We\u0000additionally find that the central regions containing a high fraction of\u0000ionized PAHs with large sizes, e.g., those in MCG-05-23-016, are likely\u0000experiencing severe photo-ionization because of the radiative effects from the\u0000radiative shock precursor besides the AGN. The severe photo-ionization can\u0000contribute to the ionization of all PAHs and further destruction of small PAHs.\u0000Overall, different Seyferts, even different regions in the same galaxy, e.g.,\u0000those in NGC,3081, can contain PAH populations of different properties.\u0000Specifically, Seyferts that exhibit similar PAH characteristics to ESO137-G034\u0000and MCG-05-23-016 also tend to have similar emission line properties to them,\u0000suggesting that the explanations for PAH characteristics of ESO137-G034 and\u0000MCG-05-23-016 may also apply generally. These results have promising\u0000application in the era of JWST, especially in diagnosing different (i.e.,\u0000radiative, and kinetic) AGN feedback modes.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lulu Zhang, Chris Packham, Erin K. S. Hicks, Ric I. Davies, Taro T. Shimizu, Almudena Alonso-Herrero, Laura Hermosa Muñoz, Ismael García-Bernete, Miguel Pereira-Santaella, Anelise Audibert, Enrique López-Rodríguez, Enrica Bellocch, Andrew J. Bunker, Francoise Combes, Tanio Díaz-Santos, Poshak Gandhi, Santiago García-Burillo, Begoña García-Lorenzo, Omaira González-Martín, Masatoshi Imanishi, Alvaro Labiano, Mason T. Leist, Nancy A. Levenson, Cristina Ramos Almeida, Claudio Ricci, Dimitra Rigopoulou, David J. Rosario, Marko Stalevski, Martin J. Ward, Donaji Esparza-Arredondo, Dan Delaney, Lindsay Fuller, Houda Haidar, Sebastian Hönig, Takuma Izumi, Daniel Rouan
Utilizing JWST MIRI/MRS IFU observations of the kiloparsec scale central regions, we showcase the diversity of ionized gas distributions and kinematics in six nearby Seyfert galaxies included in the GATOS survey. Specifically, we present spatially resolved flux distribution and velocity field maps of six ionized emission lines covering a large range of ionization potentials ($15.8-97.1$ eV). Based on these maps, we showcase the evidence of ionized gas outflows in the six targets, and find some highly disturbed regions in NGC,5728, NGC,5506, and ESO137-G034. We propose AGN-driven radio jets plausibly play an important role in triggering these highly disturbed regions. With the outflow rates estimated based on [Ne~{footnotesize V}] emission, we find the six targets tend to have ionized outflow rates converged to a narrower range than previous finding. These results have important implication for the outflow properties in AGN of comparable luminosity.
{"title":"The Galaxy Activity, Torus, and Outflow Survey (GATOS). (IV): Exploring Ionized Gas Outflows in Central Kiloparsec Regions of GATOS Seyferts","authors":"Lulu Zhang, Chris Packham, Erin K. S. Hicks, Ric I. Davies, Taro T. Shimizu, Almudena Alonso-Herrero, Laura Hermosa Muñoz, Ismael García-Bernete, Miguel Pereira-Santaella, Anelise Audibert, Enrique López-Rodríguez, Enrica Bellocch, Andrew J. Bunker, Francoise Combes, Tanio Díaz-Santos, Poshak Gandhi, Santiago García-Burillo, Begoña García-Lorenzo, Omaira González-Martín, Masatoshi Imanishi, Alvaro Labiano, Mason T. Leist, Nancy A. Levenson, Cristina Ramos Almeida, Claudio Ricci, Dimitra Rigopoulou, David J. Rosario, Marko Stalevski, Martin J. Ward, Donaji Esparza-Arredondo, Dan Delaney, Lindsay Fuller, Houda Haidar, Sebastian Hönig, Takuma Izumi, Daniel Rouan","doi":"arxiv-2409.09771","DOIUrl":"https://doi.org/arxiv-2409.09771","url":null,"abstract":"Utilizing JWST MIRI/MRS IFU observations of the kiloparsec scale central\u0000regions, we showcase the diversity of ionized gas distributions and kinematics\u0000in six nearby Seyfert galaxies included in the GATOS survey. Specifically, we\u0000present spatially resolved flux distribution and velocity field maps of six\u0000ionized emission lines covering a large range of ionization potentials\u0000($15.8-97.1$ eV). Based on these maps, we showcase the evidence of ionized gas\u0000outflows in the six targets, and find some highly disturbed regions in\u0000NGC,5728, NGC,5506, and ESO137-G034. We propose AGN-driven radio jets\u0000plausibly play an important role in triggering these highly disturbed regions.\u0000With the outflow rates estimated based on [Ne~{footnotesize V}] emission, we\u0000find the six targets tend to have ionized outflow rates converged to a narrower\u0000range than previous finding. These results have important implication for the\u0000outflow properties in AGN of comparable luminosity.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kexin Liu, Hong Guo, Sen Wang, Dandan Xu, Shengdong Lu, Weiguang Cui, Romeel Dav'e
In this study, we examine the role of circumgalactic medium (CGM) angular momentum ($j_{rm CGM}$) on star formation in galaxies, whose influence is currently not well understood. The analysis utilises central galaxies from two hydrodynamical simulations, SIMBA and IllustrisTNG. We observe a substantial divergence in how star formation rates correlate with CGM angular momentum between the two simulations. Specifically, quenched galaxies in IllustrisTNG show high $j_{rm CGM}$, while in SIMBA, quenched galaxies have low $j_{rm CGM}$. This difference is attributed to the distinct active galactic nucleus (AGN) feedback mechanisms active in each simulation. Moreover, both simulations demonstrate similar correlations between $j_{rm CGM}$ and environmental angular momentum ($j_{rm Env}$) in star-forming galaxies, but these correlations change notably when kinetic AGN feedback is present. In IllustrisTNG, quenched galaxies consistently show higher $j_{rm CGM}$ compared to their star-forming counterparts with the same $j_{rm Env}$, a trend not seen in SIMBA. Examining different AGN feedback models in SIMBA, we further confirm that AGN feedback significantly influences the CGM gas distribution, although the relationship between the cold gas fraction and the star formation rate (SFR) remains largely stable across different feedback scenarios.
{"title":"Disparate Effects of Circumgalactic Medium Angular Momentum in IllustrisTNG and SIMBA","authors":"Kexin Liu, Hong Guo, Sen Wang, Dandan Xu, Shengdong Lu, Weiguang Cui, Romeel Dav'e","doi":"arxiv-2409.09379","DOIUrl":"https://doi.org/arxiv-2409.09379","url":null,"abstract":"In this study, we examine the role of circumgalactic medium (CGM) angular\u0000momentum ($j_{rm CGM}$) on star formation in galaxies, whose influence is\u0000currently not well understood. The analysis utilises central galaxies from two\u0000hydrodynamical simulations, SIMBA and IllustrisTNG. We observe a substantial\u0000divergence in how star formation rates correlate with CGM angular momentum\u0000between the two simulations. Specifically, quenched galaxies in IllustrisTNG\u0000show high $j_{rm CGM}$, while in SIMBA, quenched galaxies have low $j_{rm\u0000CGM}$. This difference is attributed to the distinct active galactic nucleus\u0000(AGN) feedback mechanisms active in each simulation. Moreover, both simulations\u0000demonstrate similar correlations between $j_{rm CGM}$ and environmental\u0000angular momentum ($j_{rm Env}$) in star-forming galaxies, but these\u0000correlations change notably when kinetic AGN feedback is present. In\u0000IllustrisTNG, quenched galaxies consistently show higher $j_{rm CGM}$ compared\u0000to their star-forming counterparts with the same $j_{rm Env}$, a trend not\u0000seen in SIMBA. Examining different AGN feedback models in SIMBA, we further\u0000confirm that AGN feedback significantly influences the CGM gas distribution,\u0000although the relationship between the cold gas fraction and the star formation\u0000rate (SFR) remains largely stable across different feedback scenarios.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Galikyan, Sh. Khlghatyan, A. A. Kocharyan, V. G. Gurzadyan
The star cluster surrounding the supermassive black hole in the center of Milky Way is probed using the data on the S2 star. The value of precession found at the physics-informed neural networks (PINN) analysis of the S2 data is used to consider the role of the scattering of S2 star on stars of the cluster, described by a random force given by the Holtsmark distribution. The critical value for the star density of the core cluster for which the observed precession value by PINN lies inside 70% confidence interval (between 15% and 85% quantiles) around the median of precession due to scattering, is obtained as n_crit approx 8.3 10^6 pc^-3, that is at higher star densities the perturbation of the orbit of S2 would exceed the observed one.
{"title":"S2-star dynamics probing the Galaxy core cluster","authors":"N. Galikyan, Sh. Khlghatyan, A. A. Kocharyan, V. G. Gurzadyan","doi":"arxiv-2409.10567","DOIUrl":"https://doi.org/arxiv-2409.10567","url":null,"abstract":"The star cluster surrounding the supermassive black hole in the center of\u0000Milky Way is probed using the data on the S2 star. The value of precession\u0000found at the physics-informed neural networks (PINN) analysis of the S2 data is\u0000used to consider the role of the scattering of S2 star on stars of the cluster,\u0000described by a random force given by the Holtsmark distribution. The critical\u0000value for the star density of the core cluster for which the observed\u0000precession value by PINN lies inside 70% confidence interval (between 15% and\u000085% quantiles) around the median of precession due to scattering, is obtained\u0000as n_crit approx 8.3 10^6 pc^-3, that is at higher star densities the\u0000perturbation of the orbit of S2 would exceed the observed one.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xunda Sun, Xin Wang, Xiangcheng Ma, Kai Wang, Andrew Wetzel, Claude-André Faucher-Giguère, Philip F. Hopkins, Dušan Kereš, Russell L. Graf, Andrew Marszewski, Jonathan Stern, Guochao Sun, Lei Sun, Keyer Thyme
Using the FIRE-2 cosmological zoom-in simulations, we investigate the temporal evolution of gas-phase metallicity radial gradients of Milky Way-mass progenitors in the redshift range of $0.4
利用FIRE-2宇宙学放大模拟，我们研究了0.4
{"title":"The physical origin of positive metallicity radial gradients in high-redshift galaxies: insights from the FIRE-2 cosmological hydrodynamic simulations","authors":"Xunda Sun, Xin Wang, Xiangcheng Ma, Kai Wang, Andrew Wetzel, Claude-André Faucher-Giguère, Philip F. Hopkins, Dušan Kereš, Russell L. Graf, Andrew Marszewski, Jonathan Stern, Guochao Sun, Lei Sun, Keyer Thyme","doi":"arxiv-2409.09290","DOIUrl":"https://doi.org/arxiv-2409.09290","url":null,"abstract":"Using the FIRE-2 cosmological zoom-in simulations, we investigate the\u0000temporal evolution of gas-phase metallicity radial gradients of Milky Way-mass\u0000progenitors in the redshift range of $0.4<z<3$. We pay special attention to the\u0000occurrence of positive (i.e. inverted) metallicity gradients -- where\u0000metallicity increases with galactocentric radius. This trend, contrary to the\u0000more commonly observed negative radial gradients, has been frequently seen in\u0000recent spatially resolved grism observations. The occurrence rate of positive\u0000gradients in FIRE-2 is about $sim10%$ for $0.4<z<3$, and $sim16%$ at higher\u0000redshifts ($1.5<z<3$), broadly consistent with observations. Moreover, we\u0000investigate the correlations among galaxy metallicity gradient, stellar mass,\u0000star formation rate (SFR), and degree of rotational support. Our results show\u0000that galaxies with lower mass, higher specific SFR (sSFR), and more turbulent\u0000disks are more likely to exhibit positive metallicity gradients. The FIRE-2\u0000simulations show evidence for positive gradients that occur both before and/or\u0000after major episodes of star formation, manifesting as sharp rises in a\u0000galaxy's star-formation history. Positive gradients occurring before major\u0000star-formation episodes are likely caused by metal-poor gas inflows, whereas\u0000those appearing afterwards often result from metal-enriched gas outflows,\u0000driven by strong stellar feedback. Our results support the important role of\u0000stellar feedback in governing the chemo-structural evolution and disk formation\u0000of Milky Way-mass galaxies at the cosmic noon epoch.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"77 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent numerical works, including ours, lend credence to the thesis that ambient environment, i.e., external pressure, affects star-forming ability of clouds & filaments. In continuation with our series of papers on the subject we explore this thesis further by developing hydrodynamic simulations of accreting filaments confined by external pressures in the range $10^{4 -7}$ $K cm^{-3}$. Our findings are-textbf{(i)} irrespective of linemass, filaments fragment to yield spheroidal cores. Initially sub-critical filaments in low to intermediate external pressure environments form broad cores which suggests, weakly self-gravitating filaments must fragment via emph{collect-and-collapse} mode to form broad cores. Transcritical filaments, by contrast, become susceptible to Jeans-type instability and form pinched cores; textbf{(ii)} ambient environment bears upon physical properties of filaments including their {small FWHM$_{fil}$}. Only those initially suffused with subsonic turbulence in Solar Neighbourhood-like environs, however, have {small FWHM$_{fil}$}$sim$ 0.1 $pc$. In high pressure environs they not only have smaller widths, but become severely eviscerated. On the contrary, filaments suffused with initially supersonic turbulence are typically broader; textbf{(iii)} quasi-oscillatory nature of velocity gradients is ubiquitous along filament lengths and its magnitude generally increases with increasing pressure. The periodicity of the velocity gradients approximately matches the fragmentation lengthscale of filaments; textbf{(iv)} oscillatory features of the radial component of the velocity gradient are a unreliable proxy for detecting signatures of accretion onto filaments; textbf{(v)} filaments at either extreme of external pressure are inefficient at cycling gas into the dense phase which could reconcile the corresponding inefficiency of star-formation in such environments.
{"title":"On the formation of cores in accreting filaments and the impact of ambient environment on it","authors":"S. V. Anathpindika, J. Di Francesco","doi":"arxiv-2409.09431","DOIUrl":"https://doi.org/arxiv-2409.09431","url":null,"abstract":"Recent numerical works, including ours, lend credence to the thesis that\u0000ambient environment, i.e., external pressure, affects star-forming ability of\u0000clouds & filaments. In continuation with our series of papers on the subject we\u0000explore this thesis further by developing hydrodynamic simulations of accreting\u0000filaments confined by external pressures in the range $10^{4 -7}$ $K cm^{-3}$.\u0000Our findings are-textbf{(i)} irrespective of linemass, filaments fragment to\u0000yield spheroidal cores. Initially sub-critical filaments in low to intermediate\u0000external pressure environments form broad cores which suggests, weakly\u0000self-gravitating filaments must fragment via emph{collect-and-collapse} mode\u0000to form broad cores. Transcritical filaments, by contrast, become susceptible\u0000to Jeans-type instability and form pinched cores; textbf{(ii)} ambient\u0000environment bears upon physical properties of filaments including their {small\u0000FWHM$_{fil}$}. Only those initially suffused with subsonic turbulence in Solar\u0000Neighbourhood-like environs, however, have {small FWHM$_{fil}$}$sim$ 0.1\u0000$pc$. In high pressure environs they not only have smaller widths, but become\u0000severely eviscerated. On the contrary, filaments suffused with initially\u0000supersonic turbulence are typically broader; textbf{(iii)} quasi-oscillatory\u0000nature of velocity gradients is ubiquitous along filament lengths and its\u0000magnitude generally increases with increasing pressure. The periodicity of the\u0000velocity gradients approximately matches the fragmentation lengthscale of\u0000filaments; textbf{(iv)} oscillatory features of the radial component of the\u0000velocity gradient are a unreliable proxy for detecting signatures of accretion\u0000onto filaments; textbf{(v)} filaments at either extreme of external pressure\u0000are inefficient at cycling gas into the dense phase which could reconcile the\u0000corresponding inefficiency of star-formation in such environments.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tara Dacunha, Sergio Martin-Alvarez, Susan E. Clark, Enrique Lopez-Rodriguez
Understanding the role that magnetic fields play on the stage of galaxy formation requires accurate methods for inferring the properties of extragalactic magnetic fields. Radio synchrotron emission has been the most promising avenue to infer magnetic field strengths across galaxies, with the application of a central assumption: that galactic cosmic rays are in energy equipartition with the magnetic field. In this work, we leverage flexible synthetic observations of a high-resolution magnetohydrodynamic simulation of a Milky Way-like galaxy to review whether true equipartition is capable of reproducing radio observations of galaxies, and investigate its impact on the inference of magnetic field strengths when varying the properties and density distribution of the cosmic rays. We find that imposing equipartition (regardless of scale length) results in cosmic ray electron densities that are unable to generate either the amplitude or the shape of the radio intensity profiles typically observed in spiral galaxies. Instead, observationally motivated smooth distributions of cosmic ray electrons across the galaxy provide a remarkable match to observations. We further demonstrate that assuming equipartition with those mock observations can lead to significant overestimation of the magnetic field strength ($sim10-50times$). This overestimation varies with cosmic ray electron densities, cosmic ray spectrum power-law index, and galactic environment, aggravated in inter-arm regions and attenuated in star-forming regions. Our results promote caution when assuming equipartition in observations, and suggest that additional theoretical and numerical work is required to leverage the upcoming generation of radio observations poised to revolutionize our understanding of astrophysical magnetic fields.
{"title":"The overestimation of equipartition magnetic field strengths from synchrotron emission using synthetically observed galaxies","authors":"Tara Dacunha, Sergio Martin-Alvarez, Susan E. Clark, Enrique Lopez-Rodriguez","doi":"arxiv-2409.08437","DOIUrl":"https://doi.org/arxiv-2409.08437","url":null,"abstract":"Understanding the role that magnetic fields play on the stage of galaxy\u0000formation requires accurate methods for inferring the properties of\u0000extragalactic magnetic fields. Radio synchrotron emission has been the most\u0000promising avenue to infer magnetic field strengths across galaxies, with the\u0000application of a central assumption: that galactic cosmic rays are in energy\u0000equipartition with the magnetic field. In this work, we leverage flexible\u0000synthetic observations of a high-resolution magnetohydrodynamic simulation of a\u0000Milky Way-like galaxy to review whether true equipartition is capable of\u0000reproducing radio observations of galaxies, and investigate its impact on the\u0000inference of magnetic field strengths when varying the properties and density\u0000distribution of the cosmic rays. We find that imposing equipartition\u0000(regardless of scale length) results in cosmic ray electron densities that are\u0000unable to generate either the amplitude or the shape of the radio intensity\u0000profiles typically observed in spiral galaxies. Instead, observationally\u0000motivated smooth distributions of cosmic ray electrons across the galaxy\u0000provide a remarkable match to observations. We further demonstrate that\u0000assuming equipartition with those mock observations can lead to significant\u0000overestimation of the magnetic field strength ($sim10-50times$). This\u0000overestimation varies with cosmic ray electron densities, cosmic ray spectrum\u0000power-law index, and galactic environment, aggravated in inter-arm regions and\u0000attenuated in star-forming regions. Our results promote caution when assuming\u0000equipartition in observations, and suggest that additional theoretical and\u0000numerical work is required to leverage the upcoming generation of radio\u0000observations poised to revolutionize our understanding of astrophysical\u0000magnetic fields.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Suyash Deshmukh, Sean T. Linden, Daniela Calzetti, Angela Adamo, Matteo Messa, Kathryn Grasha, Elena Sabbi, Linda Smith, Kelsey E. Johnson
We present an analysis of Hubble Space Telescope (HST) data from WFC3/UVIS, WFC3/IR and ACS, investigating the young stellar cluster (YSC) population in the face-on spiral galaxy M83. Within the field of view of the IR pointings, we identify 454 sources with compact F814W continuum and Pa$beta$ line emission with a S/N $geq 3$ as possible YSC candidates embedded in dust. We refine this selection to 97 candidates based on their spectral energy distributions, multi-wavelength morphology, and photometric uncertainties. For sources that are detected in all bands and have mass $> 10^{2.8} M_{odot}$ (53 sources), we find that by 2 Myr $75%$ of infrared-selected star clusters have an $A_{V} leq 1$, and that by 3 Myr the fraction rises to $sim 82%$. This evidence of early clearing implies that pre-supernovae feedback from massive stars are responsible for clearing the majority of the natal gas and dust that surround infrared-selected star clusters in M83. Further, this result is consistent with previous estimates based on WFC3 observations, and adds to the growing body of literature suggesting pre-supernova feedback to be crucial for YSC emergence in normal star-forming galaxies. Finally, we find a weak correlation between the YSC concentration index and age over the first 10 Myr, which matches previous studies and indicates little or no change in the size of YSCs in M83 during their early evolution.
{"title":"The Clearing Timescale for Infrared-selected Star Clusters in M83 with HST","authors":"Suyash Deshmukh, Sean T. Linden, Daniela Calzetti, Angela Adamo, Matteo Messa, Kathryn Grasha, Elena Sabbi, Linda Smith, Kelsey E. Johnson","doi":"arxiv-2409.08994","DOIUrl":"https://doi.org/arxiv-2409.08994","url":null,"abstract":"We present an analysis of Hubble Space Telescope (HST) data from WFC3/UVIS,\u0000WFC3/IR and ACS, investigating the young stellar cluster (YSC) population in\u0000the face-on spiral galaxy M83. Within the field of view of the IR pointings, we\u0000identify 454 sources with compact F814W continuum and Pa$beta$ line emission\u0000with a S/N $geq 3$ as possible YSC candidates embedded in dust. We refine this\u0000selection to 97 candidates based on their spectral energy distributions,\u0000multi-wavelength morphology, and photometric uncertainties. For sources that\u0000are detected in all bands and have mass $> 10^{2.8} M_{odot}$ (53 sources), we\u0000find that by 2 Myr $75%$ of infrared-selected star clusters have an $A_{V}\u0000leq 1$, and that by 3 Myr the fraction rises to $sim 82%$. This evidence of\u0000early clearing implies that pre-supernovae feedback from massive stars are\u0000responsible for clearing the majority of the natal gas and dust that surround\u0000infrared-selected star clusters in M83. Further, this result is consistent with\u0000previous estimates based on WFC3 observations, and adds to the growing body of\u0000literature suggesting pre-supernova feedback to be crucial for YSC emergence in\u0000normal star-forming galaxies. Finally, we find a weak correlation between the\u0000YSC concentration index and age over the first 10 Myr, which matches previous\u0000studies and indicates little or no change in the size of YSCs in M83 during\u0000their early evolution.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maren Cosens, Shelley A. Wright, Karin Sandstrom, Lee Armus, Norman Murray, Jordan N. Runco, Sanchit Sabhlok, James Wiley
Measurements of oxygen abundance throughout galaxies provide insight to the formation histories and ongoing processes. Here we present a study of the gas phase oxygen abundance in the HII regions and diffuse gas of the nearby starburst dwarf galaxy, IC 10. Using the Keck Cosmic Web Imager (KCWI) at W.M. Keck Observatory, we map the central region of IC 10 from 3500-5500A. The auroral [OIII]4363A line is detected with high signal-to-noise in 12 of 46 HII regions observed, allowing for direct measurement of the oxygen abundance, yielding a median and standard deviation of $rm12+log(O/H)=8.37pm0.25$. We investigate trends between these directly measured oxygen abundances and other HII region properties, finding weak negative correlations with the radius, velocity dispersion, and luminosity. We also find weak negative correlations between oxygen abundance and the derived quantities of turbulent pressure and ionized gas mass, and a moderate correlation with the derived dynamical mass. Strong line, $rm R_{23}$ abundance estimates are used in the remainder of the HII regions and on a resolved spaxel-by-spaxel basis. There is a large offset between the abundances measured with $rm R_{23}$ and the auroral line method. We find that the $rm R_{23}$ method is unable to capture the large range of abundances observed via the auroral line measurements. The extent of this variation in measured abundances further indicates a poorly mixed interstellar medium (ISM) in IC 10, which is not typical of dwarf galaxies and may be partly due to the ongoing starburst, accretion of pristine gas, or a late stage merger.
{"title":"Oxygen Abundance Throughout the Dwarf Starburst IC 10","authors":"Maren Cosens, Shelley A. Wright, Karin Sandstrom, Lee Armus, Norman Murray, Jordan N. Runco, Sanchit Sabhlok, James Wiley","doi":"arxiv-2409.09020","DOIUrl":"https://doi.org/arxiv-2409.09020","url":null,"abstract":"Measurements of oxygen abundance throughout galaxies provide insight to the\u0000formation histories and ongoing processes. Here we present a study of the gas\u0000phase oxygen abundance in the HII regions and diffuse gas of the nearby\u0000starburst dwarf galaxy, IC 10. Using the Keck Cosmic Web Imager (KCWI) at W.M.\u0000Keck Observatory, we map the central region of IC 10 from 3500-5500A. The\u0000auroral [OIII]4363A line is detected with high signal-to-noise in 12 of 46 HII\u0000regions observed, allowing for direct measurement of the oxygen abundance,\u0000yielding a median and standard deviation of $rm12+log(O/H)=8.37pm0.25$. We\u0000investigate trends between these directly measured oxygen abundances and other\u0000HII region properties, finding weak negative correlations with the radius,\u0000velocity dispersion, and luminosity. We also find weak negative correlations\u0000between oxygen abundance and the derived quantities of turbulent pressure and\u0000ionized gas mass, and a moderate correlation with the derived dynamical mass.\u0000Strong line, $rm R_{23}$ abundance estimates are used in the remainder of the\u0000HII regions and on a resolved spaxel-by-spaxel basis. There is a large offset\u0000between the abundances measured with $rm R_{23}$ and the auroral line method.\u0000We find that the $rm R_{23}$ method is unable to capture the large range of\u0000abundances observed via the auroral line measurements. The extent of this\u0000variation in measured abundances further indicates a poorly mixed interstellar\u0000medium (ISM) in IC 10, which is not typical of dwarf galaxies and may be partly\u0000due to the ongoing starburst, accretion of pristine gas, or a late stage\u0000merger.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah M. R. Jeffreson, Eve C. Ostriker, Chang-Goo Kim, Jindra Gensior, Greg L. Bryan, Timothy A. Davis, Lars Hernquist, Sultan Hassan
We present a suite of six high-resolution chemo-dynamical simulations of isolated galaxies, spanning observed disk-dominated environments on the star-forming main sequence, as well as quenched, bulge-dominated environments. We compare and contrast the physics driving star formation and stellar feedback amongst the galaxies, with a view to modeling these processes in cosmological simulations. We find that the mass-loading of galactic outflows is coupled to the clustering of supernova explosions, which varies strongly with the rate of galactic rotation $Omega = v_c/R$ via the Toomre length, leading to smoother gas disks in the bulge-dominated galaxies. This sets an equation of state in the star-forming gas that also varies strongly with $Omega$, so that the bulge-dominated galaxies have higher mid-plane densities, lower velocity dispersions, and higher molecular gas fractions than their main sequence counterparts. The star formation rate in five out of six galaxies is independent of $Omega$, and is consistent with regulation by the mid-plane gas pressure alone. In the sixth galaxy, which has the most centrally-concentrated bulge and thus the highest $Omega$, we reproduce dynamical suppression of the star formation efficiency (SFE) in agreement with observations. This produces a transition away from pressure-regulated star formation.
{"title":"Learning the Universe: GalactISM simulations of resolved star formation and galactic outflows across main sequence and quenched galactic environments","authors":"Sarah M. R. Jeffreson, Eve C. Ostriker, Chang-Goo Kim, Jindra Gensior, Greg L. Bryan, Timothy A. Davis, Lars Hernquist, Sultan Hassan","doi":"arxiv-2409.09114","DOIUrl":"https://doi.org/arxiv-2409.09114","url":null,"abstract":"We present a suite of six high-resolution chemo-dynamical simulations of\u0000isolated galaxies, spanning observed disk-dominated environments on the\u0000star-forming main sequence, as well as quenched, bulge-dominated environments.\u0000We compare and contrast the physics driving star formation and stellar feedback\u0000amongst the galaxies, with a view to modeling these processes in cosmological\u0000simulations. We find that the mass-loading of galactic outflows is coupled to\u0000the clustering of supernova explosions, which varies strongly with the rate of\u0000galactic rotation $Omega = v_c/R$ via the Toomre length, leading to smoother\u0000gas disks in the bulge-dominated galaxies. This sets an equation of state in\u0000the star-forming gas that also varies strongly with $Omega$, so that the\u0000bulge-dominated galaxies have higher mid-plane densities, lower velocity\u0000dispersions, and higher molecular gas fractions than their main sequence\u0000counterparts. The star formation rate in five out of six galaxies is\u0000independent of $Omega$, and is consistent with regulation by the mid-plane gas\u0000pressure alone. In the sixth galaxy, which has the most centrally-concentrated\u0000bulge and thus the highest $Omega$, we reproduce dynamical suppression of the\u0000star formation efficiency (SFE) in agreement with observations. This produces a\u0000transition away from pressure-regulated star formation.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：